1. Field of the Invention
The present invention relates to a high-power switched power supply comprising a power transformer whose primary is composed of a power rectifier and of a switched element, a filter circuit being provided in the secondary circuit of the transformer following a rectifier, the filter circuit comprising two chokes respectively arranged in a series arm in the lines leading to two output terminals of at least one shunt capacitor.
2. Description of the Prior Art
Switched power supplies have the significant advantage over traditional power supplies in that they have a high efficiency given low weight and low volume and given a correspondingly lower expense. In contrast thereto, disadvantages are a somewhat more complicated circuitry, a greater radio frequency (RF) noise emission and greater difficulties in smoothing the output voltage.
Greater RF disturbances particularly occur given switched power supplies that comprise a filter choke in only one of the lines leading to the two output terminals, with the result that the RF disturbances proceed to the load by way of the other choke-free line. The integration of additional RF chokes into the two output lines, if need be in combination with Y-anti-interference capacitors, is in fact fundamentally possible, but causes a considerable expense in high-power devices because such RF chokes are very expensive because of their size.
The foregoing is also true for the case in which a power choke is interposed in each of the two output lines because the second power choke necessarily requires additional space and correspondingly added expense. As an additional complicating factor, given high-power switched power supplies, is that power chokes can practically not be "wound" because of the large line cross section.